Eyesight in Birds & Using Window Decals to Prevent Window Strikes

Our backyards will soon be a flurry of activity as our feathered friends begin their spring migration. As we begin to welcome back our flocks, we should quickly turn to ensure the proper precautions are taken care of early. Every year millions of birds are injured or killed due to window strikes and one sure-fire way to help avoid this possibility is by getting your reflective window decals up before the season really kicks into high gear!

These window decals can be applied to your home or office windows that brilliantly reflect the ultraviolet sunlight. The ultraviolet light is invisible to humans but glows like a stoplight for birds.

The main reason for this being that birds enjoy a much sharper vision than their human counterparts, with the ability to see certain light frequencies–including ultraviolet—which we humans cannot.

Many songbirds have feathers that reflect ultraviolet light. This light is used to communicate species, gender, and perhaps even social standing. Birds can see this ultraviolet light under normal, daylight conditions, while humans would require the assistance of a black light.

How Birds See Better Than Humans

Both birds and humans have photoreceptive ‘cones’ in the retina located at the back of the eye. These cones allow us to see color light. The human eye contains 10,000 cones per square millimeter. Songbirds, for example, have up to 12 times this amount or 120,000 cones per square millimeter.

In humans, these photoreceptive cones consist of three types. Each cone is sensitive to red, green, or blue light. This is called trichromatic color vision. Birds have an extra cone for tetrachromatic color vision. This extra cone expands the visible light spectrum, allowing birds to see ultraviolet frequencies.

During low-light conditions, both humans and birds rely on photoreceptive ‘cell rods’ in the retina. The human eye has 200,000 cell rods per square millimeter. Some birds, such as owls, have up to 1,000,000 cell rods per square millimeter.

In fact, bird eyes, on average, account for 15% of the mass of the bird’s entire head, while human eyes, by contrast, account for less than 2% of the head.

Bird retinas, in contrast to humans, contain no blood vessels. This prevents light scattering and thus provides birds with greater visual acuity than humans.

We carry three varieties of window decals, all of which use a component that is able to brilliantly reflect ultraviolet sunlight. To the human eye, these decals look simply like lightly frosted or etched glass, but appear as prominent as a stoplight to our feathered friends. We recommend a decal for every 3’ x 3’ stretch of glass or window to ensure the ultimate safety and fewer window strikes.

These decals are all available in-store and a package of four comes in at just under $10 at the register. Stop on in and see us!